1. Field of the Invention
The present invention relates to a mobile communication method and a mobile communication system wherein, in the case of sharing a plurality of mobile terminals for users, a call being communicated can be switched and transferred to another available mobile terminal.
2. Description of Related Art
With the recent spread of mobile communications, users have become more and more opportunities to use a plurality of mobile terminals as required.
For example, a plurality of mobile terminals for business and personal communications, or a vehicle-mounted high-power terminal and a light and small mobile terminal, or a PC card type data communication terminal and a mobile terminal with a voice function can be used as required.
With a conventional mobile communication system, a user can use the same telephone number for a plurality of mobile terminals to which the user is subscribed (Japanese Patent Application Laid-open No. 11-234748).
However, switching operations for mobile terminals are limited to one from a mobile terminal that is unavailable during the switching operation, and switching operations from an available mobile terminal are not permitted.
Further, switching operations for mobile terminals are limited to only while all of the mobile terminals are being controlled during non-communicating.
As a result, the following problems may occur.
First, to allow a plurality of mobile terminals to use the same telephone number, the device numbers of desired mobile terminals must be registered preliminarily in a database in a service control station.
Furthermore, while a user under such a contract that the same telephone number can be communicated by using a plurality of the mobile terminals, if it has become difficult to continue the communication due to the exhaustion of batteries in the mobile terminal or worsened conditions for radio wave propagation, then in spite of the plurality of mobile terminals available for the same telephone number, the user cannot continue the communication by switching a call being communicated by this mobile terminal to another mobile terminal because the switching operation is not permitted while one of the mobile terminals is used for the communication.